GB2272726A - Bolt assembly - Google Patents

Abstract

A bolt assembly comprising a bolt 2 and a housing 3 in which the bolt slides via bearing 11 and having a locked configuration in which the bolt can not be moved in a specified direction until the bolt is depressed, using knob 9, against a resilient return force provided by a spring 10, to free the bolt from a latch 6. A locking member (16 Fig. 4a) may be provided to lock the bearing 11 against the inner surface of the housing. <IMAGE>

Description

BOLT ASSEMBLY, IN PARTICULAR A DOOR BOLT ASSEMBLY This invention relates to a bolt assembly. In particular, but not exclusively, it relates to bolt assemblies for use in the bolting of doors, gates or other hinged closure apparatus.

Bolts are a very familiar means of securing a door of a hinged closure at its closed position. The typical style of bolt well known for many years comprises a circular section bolt adapted to slide within a housing, the bolt being mounted on the door and being adapted to be temporarily received in a member located adjacent the door jamb, to close the door. Such bolts normally have a locking position in which the bolt is rotated by approximately 90" and is hooked into an upper or lower portion of the housing. Such bolts are generally fairly bulky and not very secure, since they are relatively easily manipulated, by breaking through an adjacent glass panel for example, into an open position.

The present invention arose in an attempt to provide an improved bolt assembly.

According to the present invention, there is provided a bolt assembly comprising; a housing; a bar slidably located within said housing and constrained for movement relative to the housing between a first position and a second position in which the bar protrudes from the housing; means for manually manipulating the bar between the positions; a latch for co-operating with the bar in its second position to restrain the bar from moving towards its first position, and means for unlatching the bar from its second position to allow the bar to move towards the first position; said unlatching means comprising resilient means and a bearing such that pressure applied to the bar in a direction perpendicular to the sliding direction of the bar, against a resilient return force provided by the resilient means, frees the bar from the latch to enable the bar to slide to its first position.

Preferably the bar includes a transverse throughhole, in which is located the resilient means.

Advantageously, the resilient means is a compression spring mounted axially within the through hole and which acts against a bearing which contacts an inner surface of the housing. The spring may be attached at one end to the undersurface of a manipulating means such as a knob or handle.

The latch may be formed by an inturned portion of the housing, preferably by a tongue portion of the housing which is inturned a distance into the space within the housing in which the bar slides, to prevent sliding movement of the bar in one direction until the bar is depressed with respect to the housing, to free it from the latch.

The bolt assembly may further comprise a locking member located within the transverse through-hole to lock the bearing against the inner surface of the housing, thereby preventing the bar from being unlatched.

According to the present invention in a second aspect there is provided a bolt assembly, comprising a bolt and a housing in which the bolt slides and having a locked configuration in which the bolt can not be moved in a specified direction until the bolt is depressed with respect to the housing, against a resilient return force, to free the bolt from a latch and enable movement in said direction.

Preferably said direction is perpendicular to the depression direction.

A locking member may also be included to prevent the bolt from being depressed with respect to the housing.

By a bolt is meant any bolt assembly for securing a hinged structure in a closed position against a frame, jamb or other structure.

According to the present invention in a third aspect there is provided a door bolt assembly comprising any one or more of the novel features herein disclosed.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Figure 1 shows a top view of a bolt assembly; Figure 2 shows a side view of the bolt assembly in a locked position; Figure 3a shows a cross-section through the bolt assembly in an unlocked position; Figure 3b shows a cross-section through the bolt assembly in a locked position; Figure 4a shows a cross-section through a part of a second embodiment of a bolt assembly having a locking means in an unlocked position; Figure 4b shows a cross-section through a part of the second embodiment of the bolt assembly having the locking means in a locked position; Figure 5a shows a key for the locking means; Figure 5b shows a cross-section through the key tip; and Figure 6 shows schematically parts of an assembly for securing a door or other hinged structure in a closed position.

Referring to the figures, a bolt assembly such as a door bolt comprises a housing 1 and a bolt 2 slidably located within the housing for longitudinal displacement with respect to the housing. The bolt 2 is preferably rectangular in cross section and is of relatively small depth d compared to its width W (see Figure 6) so that the bolt assembly protrudes from a door face as little as possible. The housing 1 typically has an upper member 3 including a channel portion for longitudinally receiving the bolt, and a lower plate member 4, as shown in Figure 3a. Alternatively, the housing may be moulded, for example, as a unitary structure including a longitudinal rectangular cross sectional through hole in which bolt 2 slides. The top face of housing 1 includes a slot 5.

An abutment or detent 6 is formed towards one end of the channel. This detent may be formed in one embodiment by a tongue portion 6a of the upper part of the housing 3, which tongue portion is folded back upon itself, as shown in Figures 3a and 3b, to extend a distance longitudinally back into the channel. It will be appreciated that other methods of forming detents, abutments or latches may be used and the invention is not restricted to the use of any one of these.

For example, a separate piece of material could be applied to the underside of the top portion of the housing, to form a thicker part forming an abutment which latches the bolt. This separate piece of material may, for example, be spot welded or rivetted to the housing.

Alternatively, the abutment may be formed by an indentation in the housing, which may be formed by stamping or otherwise.

Bolt 2 includes a transverse aperture or throughhole 7. An operating member 8 is located within this aperture 7, which member 8 terminates in an outsize knob 9. Member 8 is of a diameter such as it can slide with respect to slot 5 and thus constrain relative movements of the bolt 2 to those allowed by the length of the slot 5. Knob 9 is preferably of larger diameter than the width of slot 5. A compression spring 10 is mounted within member 8 between knob 9 and a ball-bearing 11.

Since member 8 is open at its lower end ball-bearing 11 is adapted to contact the upper wall of the lower part of the housing. The purpose of the bearing is to enable relatively easy, low friction sliding movement and to avoid the possibility of the spring, or another part of the bolt, scratching the housing surface. In some embodiments, this bearing may be omitted. Other types of resilient members and bearing means than compression springs and ball-bearings may be used. For instance, the housing may be coated with a low friction substance such as Teflon (Trade Mark). Springs such as tension springs or leaf springs may be used.

The housing and/or the bolt may be of metal or other material and may be coated for decorative or other effect.

To operate the bolt assembly, the knob 9 is displaced sidewardly from the position shown in Figure 3a to the position shown in Figure 3b when member 8 may abut against the front edge of slot 5. At this position, the end 12 of the bolt passes the detent 6 and thus the bolt is forced upwards slightly by the return pressure of the spring against the bearing. The end 12 is thus held secure and latched within the detent and the bolt cannot slide back (towards the right in the figure) until the return force of the spring is overcome and the bolt is pushed downwards to unlatch from the detent. The position shown in Figure 3b is therefore the position at which the bolt may be locked to a co-operating member on a door jamb or frame for example.In this position, the bolt cannot be moved backwards by a simple sliding motion and a high level of security is obtained, particularly if the spring is of relatively high strength and compression.

Preferably, a slot or other aperture may be formed in the side of the casing as shown at 13 in Figure 2 and a further locking member may be applied through this slot to further prevent movement of the bolt. This locking member may be a pin or, more preferably, may be a lockable padlock.

In a variation, the slot may be formed in the bolt itself, (at the left end of the bolt shown) through which a pin or other device is secured to prevent return movement of the bolt.

When it is desired to release the bolt, pressure must be applied to knob 9 against the return force of spring 10 in a generally axial direction relative to the spring 10. This serves to release end 12 of the bolt from latch 6 and enables the bolt to be slid back to its unlocked position. A detent or latch may also be provided in this unlocked position.

A second embodiment of this invention comprises an additional locking feature for extra security, as shown in Figures 4a and 4b. Referring to these figures, operating member 8 includes an axial hole 14 extending through knob 9 and having an internal screw thread.

Located within the through-hole 14 is a bearing 15, a compression spring 10 and a locking member 16. The bearing is not spherical but is a turned member having an arcuate, e.g. hemispherical, lower surface for contacting the inner surface of the housing, and having a stem which extends into the through-hole 14. (This bearing may also be used in the embodiment of Figure 3, or in other embodiments). The locking member 16 comprises an external screw thread for co-operating with the internal screw thread of the operating member 8 and two recesses on opposite faces, one recess 20 adapted to accommodate the tip of the bearing stem and one recess 21 adapted to accommodate the tip of a key. The key may be an Allen type key, for example.

Figures 5a and 5b show a key 17 for operating the locking member. The tip of the key 18 is hexagonal in cross-section and fits snugly into the appropriately shaped recess 21 of the locking member which is also hexagonal in cross-section. Other shapes of key may equally be used.

Figure 4a shows the bolt 2 locked against movement by the latch (not shown). To release the bolt, knob 9 is depressed against the return force of the spring to free the bolt from the latch.

Figure 4b also shows the bolt locked against movement by the latch but in this figure the locking member 16 has been rotated into contact with the tip of the bearing stem using the key 17. As the bearing is forced rigidly into contact with the inner surface of the housing by the locking member 16, pressure applied to knob 9 in a generally axial direction will not depress the knob and so the bolt can not be released from the latch.

Even when the bar is unlatched, the locking member can be used to prevent the sliding movement of the bolt with respect to the housing by locking the bearing firmly into contact with the housing.

Figure 1 shows how the bolt assembly may be fastened to a door or other assembly by means of fastenings such as screws (not shown) applied through pre-formed holes 19 in the housing.

In one example, these holes are formed by rivets which are used to attach the two parts of the housing.

This has the advantage that, in a two piece housing, the rivets are not seen in use as they are hidden by the screws attaching the housing to a door or other structure. The parts of the housing may of course be attached by other means. One example of these is by spot welding.

For maximum security, it is preferred to use two keeps with the bolt assembly, as shown in Figure 6.

These comprise a first keep 22 which is mounted on the edge of the door jamb such that slot 23 is in line with the path of the bolt 2. A second keep 24 is of channelled shape, generally similar to the channel part of the housing 1 of the bolt. This is mounted on the face of the door jamb or on the adjacent wall. In effect, its plane lies at 900 to the plane of first keep 22. The combination of both keeps makes it very difficult for an intruder to compromise the security of the system since he would need to remove screws (or other fastenings) 25 holding the keeps in place in at least two generally orthogonal planes. This is nearly impossible if he is working from a limited access point, perhaps without a direct line of vision, as would be the case if he had broken through a glass panel for example.

Claims (16)

1. A bolt assembly comprising a housing; a bar slidably located within said housing and constrained for movement relative to the housing between a first position and a second position in which the bar protrudes from the housing; means for manually manipulating the bar between the positions; a latch for co-operating with the bar in its second position to restrain the bar from moving towards its first position, and means for unlatching the bar from its second position to allow the bar to move towards the first position; said unlatching means comprising resilient means and a bearing such that pressure applied to the bar in a direction perpendicular to the sliding direction of the bar, against a resilient return force provided by the resilient means, frees the bar from the latch to enable the bar to slide to its first position.

2. A bolt assembly as claimed in Claim 1, wherein the bar includes a transverse through-hole in which the resilience means is located.

3. A bolt assembly as claimed in Claim 2, wherein the resilient means is a compression spring mounted axially within the hole.

4. A bolt assembly as claimed in any preceding claim, wherein the resilient means acts against the bearing and the bearing is in contact with an inner surface of the housing.

5. A bolt assembly as claimed in any preceding claim wherein the bearing is spherical.

6. A bolt assembly as claimed in any preceding claim wherein the bearing comprises an arcuate portion for contacting an inner surface of the housing and an elongate portion for extending axially into the transverse through hole of the bar.

7. A bolt assembly as claimed in any preceding claim, wherein the latch is formed from a tongue portion of the housing inturned a distance into a space within the housing in which the bar slides.

8. A bolt assembly as claimed in any preceding claim, wherein the transverse through-hole also accommodates a locking member adapted to lock the bearing against the inner surface of the housing.

9. A bolt assembly as claimed in Claim 8, wherein the transverse through-hole has an internal screw thread adapted to co-operate with an external screw thread of the locking member.

10. A bolt assembly as claimed in Claim 8 or Claim 9, wherein the locking member is adapted to accommodate a key.

11. A bolt assembly as claimed in any preceding claim wherein the locking member comprises an external screw thread, a first recess adapted to accommodate a key, and a second recess adapted to accommodate part of the bearing.

12. A bolt assembly as claimed in Claim 11 when dependent upon Claim 6, wherein the second recess of the locking member is adapted to accommodate the free end of the elongate portion of the bearing.

13. A bolt assembly comprising a bolt and a housing in which the bolt slides and having a locked configuration in which the bolt can not be moved in a specified direction until the bolt is depressed with respect to the housing, against a resilient return force, to free the bolt from a latch and enable movement in said direction.

14. A bolt assembly as claimed in Claim 13 wherein the bolt moves in a direction perpendicular to the direction of depression.

15. A bolt assembly as claimed in Claim 13 or Claim 14 further comprising a locking member adapted to prevent the bolt from being depressed with respect to the housing.

16. A bolt assembly substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.